It's a scary concept to be sure. It does make me wonder, however how it wasnt triggered when the Earth was still highly geologically active with volcanoes constantly spewing the Earth's contents into the atmosphere.
If that didn't make it occur, what prevented it? If it did occur, then it was clearly a temporary state that Earth has some mechanism to mitigate to return to something resembling its current state on a massive enough timeframe. Interesting stuff.